DHCP + DNS server on same box?

To: misc_(_at_)_openbsd_(_dot_)_org

Subject: DHCP + DNS server on same box?

From: "Gary Hennigan" <gary_(_at_)_ieee_(_dot_)_org>

Date: 30 Oct 2001 13:58:09 -0700

Organization: none

If my ignorance as a new OpenBSD user shows ignore it...
I'm in the process of setting up my home LAN. Here's what it'll look
like:
To Cable Provider
|
| DHCP
|
---X-----
| xl0 |
| |
| OpenBSD |
| |
| dc0 |
---X-----
|
| 192.168.x.1
|
--X---
| HUB |
| X----- 192.168.x.10
| |
| X----- 192.168.x.11
| |
| X----- 192.168.x.x
| |
------
In addition to serving as my firewall I'd like my OpenBSD box to
server as a DNS server and a smarthost for internal to external email,
as well as an IMAP server for my internal network. I'm sure there are
security implications for running all these services on the firewall,
but I'm handy enough with nmap that I think I can minimize these. The
reason for configuring things this way is that the OpenBSD box will be
the only box up 24/7.
I want to configure BIND such that it serves as the DNS server for my
internal network and forwards all other requests on to my cable
providers DNS servers. If everything were static it'd be a snap, but
I've never used a box that's connected via DHCP for this purpose. Has
anyone done anything like this that's willing to share some tips? Am I
going to be stuck hacking the dhclient-script so that instead of going
into resolv.conf the nameservers are placed into the bind
configuration file as forwarders and then restart bind?
Thanks!
Gary Hennigan